1. Field
This embodiment relates to a light emitting device driving module, and more particularly to a light emitting device driving module capable of implementing a high color rendering index.
2. Description of Related Art
A light emitting diode (LED) is a light source which is environmentally friendly and has a high efficiency, so that it has become popular. The LED is used in various fields, for example, display, optical communication, automobile and general lighting. Particularly, there has been increasing demand for a white light emitting diode creating white light.
In general, a correlation color temperature (CCT) and color rendering index (CRI) are used as a performance indicator for evaluating the characteristics of the white light. The white light is closer to sunlight (natural light) with the increase of the CRI. In particular, the CRI is used as an important indicator for evaluating the performance of the white light. The CRI represents how much the color of a thing is changed when the sunlight is irradiated to the thing and when an artificial light source (lighting, etc) is irradiated to the thing. The color of the thing is defined as 100 when the sunlight is irradiated to the thing. That is, the CRI represents how close the color of the thing to which the artificial light source is irradiated is to the color of the thing to which the sunlight is irradiated. The CRI is represented by a numerical value between 0 and 100. A conventional white light emitting diode has a low CRI.
Therefore, a try has been made to implement a high CRI by using a light emitting diode package (LED) phosphor. However, the conventional LED package has luminous efficiency degradation of 20% on average when the minimum CRI is set as 80. When the high CRI is implemented by using a normal white LED and red LED, a red LED package should be additionally configured and a separate power supply and control circuits are required for driving a red LED chip.